The presenter captioned the photo: “The best surprise ever. “
The picture featured her with two sons, and husband Charlie holding up a board that said “Baby number three on the way.”
Alex’s celebrity friends were quick to congratulate the star in the comments below.
Former co-presenter Matt Baker commented: “Beautiful News- just sorry I’m not there to cover your Maternity this time around XXX lots of Love from all the Bakers (but you know that anyway).”
Louise Redknapp wrote: “Congratulaitons.”
While Kirsty Gallacher penned: “Congratulations Alex!”